The heart of a computer is a magnetic hard disk drive (HDD) which typically includes a rotating magnetic disk storage medium, a magnetic head (or slider) that includes one or more reading elements and/or one or more writing elements, a suspension arm above the rotating disk, and an actuator arm that swings the suspension arm to place the magnetic head over selected circular tracks on the rotating disk. The magnetic head floats so close to the surface of the magnetic disk that head contact may occur, possibly with detrimental effect on the reading and/or writing elements within the head.
In order to protect the reading and writing elements of the magnetic head, a protective film is formed at the air bearing surface (ABS) of the magnetic head (or slider). However, when the frequency of contact with the disk increases as the clearance is narrowed, there is a possibility that significant abrasion of the protective film and reading and/or writing elements therebeneath will occur. The amount of abrasion may be reduced by increasing the film thickness of the lubricant on the disk.
However, the thicker the lubricant film becomes, the greater the clearance between the disk and the head. In order to reduce the clearance, a lubricant that is capable of suppressing the head abrasion in a thin film while retaining the adsorbability to a disk is desired. According to Japanese Patent No. JP2010-282707A, adsorbability to a disk may be retained by having polar groups at the terminals and an aromatic ring at a center of a lubricant molecule, but with this formulation, a lubricating property of the molecule is lost and therefore there is a possibility of increasing the head abrasion, instead of reducing it.